Well, we had both extremes, just to disclose that. The mild version was promising croissants with another mail account, but I also once came back to see that m

Well, we had both extremes, just to disclose that. The mild version was promising croissants with another mail account, but I also once came back to see that my wallpaper had been changed to a still from a gay porn movie. I think my visible confusion and slight shock was quite entertaining. Of course the second prank can only be done with co-workers you know well, otherwise you could probably end up having to talk to HR.